Pressure regulators are utilized in a variety of irrigation systems. For example, pressure regulators function to maintain a predetermined pressure and/or lower pressure generally downstream of a main or primary irrigation line. For example, a pressure regulator is often used to regulate water pressure from a primary irrigation line to a sprinkler. What is needed is a mechanism for turning the flow of fluid on and off at the pressure regulator and preferably an actuating mechanism that inherently drains when fluid is removed from the system.